The explosive properties of tetrasulfur tetranitride, S4N4, are reviewed and analysed. S4N4 is an explosive compound with an impact sensitivity comparable to pentaerythritol tetranitrate (PETN) (Ei=4 J) but a friction sensitivity equal or even lower than lead azide (F=0.1–1 N). S4N4 has primary explosive properties. It has a working capacity greater than silver azide, AgN3, and is capable to initiate TNT. S4N4 shows an unusual non‐linear density/detonation velocity relationship which is due to different stability regimes of sulfur species present in the Chapman Jouguet zone. S4N4 is stable, non‐ageing, non‐toxic, insoluble in water and hence an interesting candidate for future lead tricinate replacement.